Huge Gas Mileage Increase -ATF Flush

Guys, I'm not mechanic, but have to share this ... Even though it makes no sense to me. My Taco was bought new and currently has 110k miles. I have done some moderate towing. When new, I might have seen 20mpg on the highway .. OCCASIONALLY. Over the years,MPG dropped to 16.5 to max of 17. I have done all maintenance regiously. Although I had the ATF pan drained ... Never did a flush. There were so many threads saying not so do that. Well, 2 weeks ago, I had Jiffy Lube flush the ATF. Gas mileage has leaped to over 20 MPG ... on the engine monitoring system, I register 21.5 on the highway. Easily 4 MPG better. So, I cannot believe the ATF flush could make this much a difference ... but it is the only variable. Just thought I would share this experience. I has been a welcome change at $3.90 + per gallon.

 

Could be related to a fluid with lower viscosity than the stock fluid, or possible they increased the psi in your tires while it was there?

 

I can't believe you let Jiffy Lube touch your Tacoma

 

This gives me some hope that there's a chance I can get some mpg back. My truck is TERRIBLE. I was just starting to plan out a bunch of maintenance that I wanted to do soon and a trans service was on the list but I hadn't planned on the flush since I can't do that myself. I'm rethinking that now...

 

I would never let jiffy lube touch my truck even for a oil change. My truck is awful on fuel thats why I got a 4 banger older civic now for a daily.

 

Coincidence, and possibly winter fuel being phased out. Check it manually and get back to us in 2-3 months. A tank or 2 is easily an anomaly. The ATF service had nothing to do with it.

 

Maybe your atf level was off and not shifting proper now you are at the correct level...
But I agree with coincidence for now.

Edit: jiffy lube
Don't trust your truck to them.

 

You will be back at jiffy schlube when ur trans fucks up
Good luck

 

Actually wouldn't lower viscosity fluid translate to more slippage in the torque converter = lower mpgs?

 

IDK what came out or what went in, but I know LV fluids are supposedly better on mpg. It would depend on a bunch of factors for the OP's specific application and driving conditions, but I'm thinking the fluid doesn't have much of anything to do with the mpg increase though unless it was actually syrup in there.

 

Changing the ATF should not impact fuel mileage.
I had a Toyota dealer do an AT flush and they sprayed ATF all over the engine compartment. Never Jiffy Lube. What are you going to do?

 

X2

 

Maybe they also cleaned the MAF and forgot to mention it